Taeniura lymma

Taeniura lymma, commonly known as blue-spotted stingrays, is found primarily in the Indo-west Pacific. They may be found in shallow continental shelf waters ranging from temperate to tropical seas. They prefer areas with sandy or sedimentary substrates in which they bury themselves. Sightings of Taeniura lymma have been recorded in Australia in shallow tropical marine waters from Ningaloo Reef, Western Australia to Bundaberg, Queensland. They can be found at depths of up to 25 m and have also been recorded to range in location from southern Africa and the Red Sea to the Solomon Islands. (Taylor, 1997)

Taeniura lymma is found on sandy bottoms around coral reefs. These rays like to bury themselves just underneath the sand where they will feed on various invertebrates. They usually are found on shallow continental shelves; however, they have also been observed around coral rubble and shipwreck debris at depths of 20-25m deep. Divers and snokelers will often detect this ray by its distinctive ribbon-like tail poking out from a crack in the coral. These rays are most abundant inshore. (Allen, 1996; Taylor, 1997)

Taeniura lymma is a colorful stingray with distinct, large, bright blue spots on its oval, elongated body. The snout is rounded and angular with broad outer corners. The tail tapers and can be equal to or slightly less than the body length when intact. Its caudal fin is broad and reaches to the tip of the tail. At the tip of the tail are two sharp venomous spines which permit this ray to strike at enemies forward of its head. The tail of Taeniura lymma can be easily recognized by the blue side-stripes found on either side. It has large spiracles that lie very close to its large eyes. It can grow to a disc diameter of about 25 cm but has been reported as being as large as 95 cm in diameter. The mouth is found on the underside of the body along with the gills. Within the mouth are two plates, which are used for crushing the shells of crabs, prawns, and mollusks. (McEachran, 2004)

When blue-spotted stingrays are born, they hatch out of egg cases and are pale gray or brown and are spotted with black or rusty red and white. These patterns and markings are distinct to each individual within a litter. As adults, they are olive-gray or gray-brown to yellow dorsally and white ventrally with numerous blue spots. When born, the young stingrays are about nine cm long and can grow to around 25cm as adults. The young are born out of egg cases with a soft tail that is encases in a thin layer of skin to prevent injury to the mother during birth. The skin is eventually lost and the tail is used as a protective mechanism. (Taylor, 1997)

The lifespan of Taeniura lymma is still unknown.

Blue-spotted stingrays may be found alone or in small groups, mostly in shallow waters over reef flats. they are rather shy and will usually swim away rapidly if disturbed by divers. When threatened, blue-spotted stingrays will use their venomous tail to inject poison. The venom is produced and delivered into narrow groves running lengthwise along the underside of the stinger. The entire structure is covered by a thin layer of skin which, when broken, releases its venom into its victim. (Taylor, 1997)

Propulsion in Taeniura lymma is achieved using its pectoral fins which make up the bulk of its oval, disc shaped body. Blue-spotted stingrays have fin muscles which are found throughout the entire length of the fin. All of these muscles are active except at low speeds when they are not needed to propel the body through water. (Rosenberger, 1999)

Taeniura lymma uses electroreception to communicate with other members of its species. Blue-spotted stingrays,use strucutres called the ampullae of Lorenzini, which allow them to detect slight electrical impulses within the water. This electroreception is often used as a means of recognizing members of the same species. (Taylor, 1997)

Taeniura lymma has very distinct feeding behaviors. During high tide, it migrates in groups into shallow sandy areas of tidal flats to feed on sand worms, shrimps, hermit crabs, and small fishes. At low tide it recedes back into the ocean, usually alone to hide in the coral crevices of the reef. (Taylor, 1997)

Blue-spotted stingrays will feed on many things such as bony fish, crabs, shrimp, polychaetes and other benthic invertebrates. Since the mouth is located on the underside of the body, food is trapped by pressing the prey into the substrate with their discs. The food is then directed into the mouth by maneuvering the disc over the prey. (McEachran, 2004)

Taeniura lymma can detect its prey through an electroreceptor system. The nostrils are partly covered with a broad fleshy lobe, known as the internasal flap. This is covered in sensory pores and extends to the mouth. These pores form part of the ampullae of Lorenzini (the electrorecption system.) This electroreceptor system can detect electrical fields produced by the prey. This electroreceptor system cannot only be used to detect prey but can also be used to detect predators and other members of the same species. (Taylor, 1997)

The most dangerous predator to blue-spotted stingrays are human beings. Blue-spotted stingrays are a popular ray to have in aquarium tanks. However, Taeniura lymma is very hard to take care of in an at-home aquarium. Besides humans, the only other type of predator known to this species of stingrays is the hammerhead shark. The hammerhead shark uses the cartilaginous projections form the side of their heads to pin them down to the bottom of the substrate while taking bites from the stingray's disc. The hammerhead is able to avoid being stung by the poisonous spines on the rays tail by pinning the stingray down. (Taylor, 1997)

Taeniura lymma plays an important role in their ecosystem. Taeniura lymma is a secondary consumer. It feeds on nekton such as bony fish. It also feeds on zoobenthos organisms including benthic crustaceans like crabs, shrimp/prawns, and worms such as polychaetes.

The sting that of blue-spotted stingrays may be very painful. (McEachran, 2004)

Taeniura lymma is a popular aquarium pet. Their beautiful coloration makes them a prime candidate for an aquarium pet. In Australia, Taeniura lymma is often eaten and hunted for its meat. (McEachran, 2004)

Although this species is very wide ranging and common, it is subject to human-induced problems because of capture by inshore fisheries and its attractiveness for the marine aquarium fish trade. Another major threat to this species is the destruction of its coral reef habitat. Without a habitat in which to live, this species may be pushed to extinction along with other species of the coral reef habitat. (McEachran, 2004)

The body of Taeniura lymma is made completely out of cartilage and contains no bone whatsoever. The stinging barbs on its tail can be regenerated if broken off. One interesting fact about the venom that is contained within the stinging barbs is that it can be broken down by heat. Therefore, if you ever encounter one of these magnificent animals and happen to get stung, immediately soak the wound in hot water in order to break down the venom and reduce the pain. Another interesting fact about Taeniura lymma is that it is one of the few species of rays that can retain their urine. (Webb, 1980)